Abstract

The relationship among four flow instabilities of turbomachines, namely, surge, rotating stall, cavitation surge, and rotating cavitation, is elucidated, using a unified or common model for their analysis. The simplest unifying model was employed in the analysis to focus on the characteristic features of each instability. Moreover, the concentration is on the stability criteria, and hence, the amplitudes are assumed small. Of course, the instabilities often grow to amplitudes comparable with the average value of the flow variable. Flows upstream and downstream of the impeller were assumed to be one dimensional for surge and cavitation surge and to be two dimensional for rotating stall and rotating cavitation, respectively. Viscous effects were taken into consideration in the form of cascade loss. Impeller blade geometry was incorporated in the assumption that the flow is perfectly guided. The peripheral wavelength of the disturbance was assumed to be much larger than the blade pitch.

Item Type:

Article

Additional Information:

Presented as Paper 99-2678 at the AIAA/ASME/SAE/ASEE 35th Joint Propulsion Conference and Exhibit, Los Angeles, California, 20–24 June 1999; received 30 August 1999; revision received 2 May 2000; accepted for publication 27 October 2000.
Originally published as 'Uni�fied Treatment of Flow Instabilities of Turbomachines',Tsujimoto et al, Journal of Propulsion and Power 17(3):636-43. Copyright c2000 by the American Institute of Aeronautics and Astronautics, Inc. Reprinted with permission.